[unreadable] Bio-medical advances have lowered the incidence of the index diseases traditionally associated with vitamin D deficiency, rickets and osteomalacia. Within the past several years, however, a growing body of evidence has emerged that less severe vitamin D deficiency (vitamin D insufficiency) may impair gastrointestinal absorption of calcium and contribute to the evolution of osteoporosis in older populations. In addition, further studies have implicated vitamin D in the pathogenesis of a wide variety of clinically important non-skeletal diseases. These advances have helped establish that vitamin D insufficiency/deficiency in Western populations may underlie a heterogeneous group of disorders and be reaching near epidemic proportions. Scientists from a number of disciplines have contributed to an astonishing increase in our knowledge of vitamin D related diseases and treatment. In part because of this expanding knowledge base there exist a number of unresolved conflicts regarding appropriate diagnostic criteria and treatment for vitamin D related diseases. This adds urgency to efforts to pursue further research advances, clarify recent discoveries and disseminate scientific advances into the clinical arena. We believe it is critical to bring together clinical, basic and translational investigators to reach unified conclusions about the identification, diagnosis and treatment of vitamin D related disorders, and the proposed conference will serve as an important step towards clarifying many aspects of the emerging scientific data. We plan to use this forum to encourage thought leaders in a variety of disciplines to formulate a prioritized list of the key questions, which must be tackled in order for the vitamin D field to advance. The American Society for Bone and Mineral Research is the premier society for the study and advancement of basic and clinical research in disorders relating to the skeleton. The considerations described above make it very clear that this is the time for senior thought leaders, mid-career investigators and young investigators to meet with NIH Institute staff. Information derived from the exchanges at such a meeting will serve to provide the NIH novel ideas about programs worthy of support in future years and lead to a vibrant exchange of ideas and a definition of vital pathways for future advances in research and treatment. [unreadable] [unreadable]